Whilst skin care products generally won't deliver nutrients deep into the actual living cells beneath the superficial layers of the skin, the vitamin E in many products is actually useful. Scientists have found that by applying antioxidants to the skin, free radical damage that would normally occur through exposure to UV light (say, from the sun), can be prevented or at least minimized. Vitamin E is a popular ingredient in many skin care creams.

The scientists found that the protective effects of vitamin E from that period of UV exposure were apparent 2 and 3 days later. The group of people who had vitamin E cream applied to their skin had less signs of inflammation than the group who were given the lotion without vitamin E. Inflammation is a sign of cell damage, and was measured in this study by the amount of blood flow to that area as compared to normal. This was a placebo controlled, double blind study, which means that some people received the lotion with vitamin E, some didn't and neither group knew which it was getting. The conclusions these scientists made were that vitamin E was effective at preventing the visible signs of aging on skin.

Whilst vitamin E in creams and lotions will benefit the skin, there is strong doubt on whether it can help in some of the beauty products it is in. For example, when vitamin E is advertised as being of benefit to strengthen or thicken eyelashes, this is something of a misnomer, and is not supported by science. Paula Begoun, the 'cosmetic cop' writes that there isn't a product out there that will strengthen and thicken eyelashes. The best you can do in this instance is to apply an eyelash primer and mascara to make eyelashes appear thicker. Vitamin E is an antioxidant, and the research verifies only benefits that relate to this antioxidant activity.

Another of the promises associated with vitamin E creams is that it helps to heal scars. This is not something that has been verified scientifically. Research quoted in Wikipedia found that when vitamin E was applied to patients who had undergone surgery, it did not reduce the size, shape, or color of scars. In fact, up to one third of patients experienced complications like allergies, dermatitis, and irritation that in fact can make a forming scar worse. Activated manuka honey is a much better option in reducing scarring, and healing skin.

Vitamin E remains an excellent antioxidant. It is helpful when taken as a supplement for a whole host of issues, including protecting the liver, and minimizing the damage smoking does. And it is great for the skin in terms of preventing sun damage from the oxidizing effect of UV light. It is a good 'beauty vitamin' when taken as a supplement. Erica Angyal describes how it protects cell membranes from damage and helps maintain their flexibility, which can diminish as we age. It also works to increase the level of vitamin A in our body. And it is very beneficial for skin problems like acne and psoriasis. She recommends taking 400 to 800 IU of vitamin E a day, to prevent premature aging and improve the lustre of skin.

References:
http://www.cosmeticsdesign.com/news/ng.asp?id=62583
Erica Angyal, Gorgeous Skin In 30 Days (Lothian Books, 2005)